/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 86187
 * Date: 2022-04-15
 * Time: 21:16
 */

//Scanner scan = new Scanner(System.in);

//判断一个数是否为素数
import java.util.Scanner;
public class PrimeNum {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        int i = 0;

        for (i = 2; i <= (int)Math.sqrt(num); i++) {

            if(num % i == 0) {
                System.out.println(num+"不是素数！");
                break;
            }

        }

        if(i >= (int)Math.sqrt(num))
            System.out.println(num+"是素数！");

    }
}
